Conventionally, there have been disclosed various methods in which a part of a medium surface, where magnetic ink characters (MICR characters) are printed, is read by using a magnetic head so as to obtain a magnetic regeneration signal for the purpose of character recognition. The magnetic ink characters (MICR characters) are used for checks and the like to be used in financial facilities. Character types thereof typically include E13B and CMC7, and the character types are standardized by ISO 1004 and so on.
At the initial stage in the history of development of the technology for recognizing MICR characters, a major method for character recognition involved reading a magnetic character line by using a magnetic head, inputting a waveform of the magnetic regeneration signal into a logical circuit, and then recognizing the character according to characteristics of a peak position and an output level in the waveform of the magnetic regeneration signal. However, in association with technical advancement of the performance of microprocessors as well as enhancement of memory units in relation with their high-speed operation and large capacity, character recognition by processing a magnetic signal with software has been increasing these years. Furthermore, examples of character recognition include some cases in which not only a magnetic signal but also an image captured by scanning a medium are used together.
In a disclosed method in which a magnetic signal is used, peak intervals in a waveform of a magnetic regeneration signal of a character are determined; and then, according to a combination pattern of the peak intervals, the waveform is correlated with a character having a combination pattern of the peak intervals (For example, refer to Patent Document 1 and Patent Document 2).
[Patent Document 1]
Japanese Unexamined Patent Publication (Kokai) No. JP2001-351062
[Patent Document 2]
Japanese Unexamined Patent Publication (Kokai) No. JP2005-157982
However, among checks and so on used practically in the marketplace, some include poorly printed magnetic ink characters even though the characters are still within an allowable range. Therefore, it is required that the technology of character recognition shall recognize those characters within such a border range, being free from any false character recognition.
To describe more in detail, magnetic ink characters being practically used include variations, depending on qualities of magnetic ink, a printing machine, irregularities of medium transfer speed and magnetic properties of a regeneration magnetic head and a magnetizing head. Eventually there arise alterations in the magnetic ink characters; such as a high magnetic force, a low magnetic force, a thick-lined character, a thin-lined character, tilt, and so on.
Furthermore, depending on using condition and storage condition of a check, there may also arise other alterations in the characters, such as having an opening, an unclear character, and a blurring character, etc. so that waveforms of magnetic regeneration signals are deformed in various ways. Especially, depending on the printing machine, sometimes the characters may be printed, possibly having their character pitch and character width that significantly deviate from the standards. In such a case, accuracy of the magnetic character recognition may be impaired. From that viewpoint, in the case of Patent Document 2 described above, a determination frame having a constant length is specified for segmenting a character out of a waveform of a magnetic regeneration signal. However, when the character pitch is unexpectedly long, such a method is likely to make a mis-determination on character boundary positions and probably lead to false recognition.
Thus, at least an embodiment of the present invention may provide a method and an apparatus for magnetic character recognition for recognizing magnetic characters with high accuracy, even when the magnetic ink characters are printed, having their character pitch and character width that are unusual.
To solve the problem identified above, at least an embodiment of the present invention may provide any or all of the following aspects:
(1) A method of magnetic character recognition through reading a character string by using a magnetic head, and creating a regeneration waveform for the character recognition; the character string including a plurality of magnetic characters printed with magnetic ink; and the method of magnetic character recognition including: a peak detection process for detecting peak positions in the regeneration waveform; a character pitch measuring process for calculating an average character width and an average character period of each character according to a detection result of the peak detection process; a character segmentation process for calculating a peak interval array for each character according to the average character period; a peak searching process for searching for peak positions by using searching conditions, which are different from what the character segmentation process applies, on each waveform part segmented through the character segmentation process; a peak count evaluation process for choosing either a result of the character segmentation process or a result of the peak searching process, depending on whether the number of peaks in the waveform part agrees with a prescribed number of peaks; and a character determining process for a matching operation on a peak interval array, according to the peak interval array determined through the peak count evaluation process, to determine the character.
According to at least an embodiment of the present invention; in the method of magnetic character recognition reading a character string by using a magnetic head, and creating a regeneration waveform for the character recognition, wherein the character string including a plurality of magnetic characters printed with magnetic ink; peak positions in the regeneration waveform are detected, an average character width and an average character period of each character are calculated, a peak interval array is calculated according to the average character period to segment a character, peak positions are (re-)searched by using searching conditions which are different from what the character segmentation process applies, and a peak interval array to be used for character determination is chosen by taking notice of the number of peaks in each waveform part. Therefore, the accuracy of character recognition can be improved.
Namely, the average character width and the average character period of the regeneration waveform are calculated beforehand. Then, between the peak interval array calculated according to the average character period and the other peak interval array obtained by searching operation and calculation under searching conditions, which are different from those used for calculating the former peak interval array, a more suitable one is chosen by taking notice of the number of peaks in the waveform part. Therefore, it is possible to recognize magnetic characters with high accuracy, even when the magnetic ink characters are printed, having their character pitch and character width that are unusual owing to uncertainties in printing condition.
(2) The method of magnetic character recognition: wherein the character pitch measuring process calculates the average character width and the average character period by calculating peak difference values of the regeneration waveform and using a histogram of the peak difference values.
According to at least an embodiment of the present invention; the character pitch measuring process calculates peak difference values of the regeneration waveform, and then calculates the average character width and the average character period by using a histogram of the peak difference values. Accordingly, the accuracy of character recognition can be improved easily. Furthermore, making use of difference processing generally, such as calculating peak difference values, can prevent programs from becoming heavy-laded.
(3) The method of magnetic character recognition: wherein the character pitch measuring process calculates the average character width and the average character period by calculating the peak difference values of the regeneration waveform and the cumulative frequency distribution thereof, and calculating a flatness of the cumulative frequency distribution.
According to at least an embodiment of the present invention; the character pitch measuring process calculates the peak difference values of the regeneration waveform and the cumulative frequency distribution thereof, and then calculates the average character width and the average character period by calculating a flatness of the cumulative frequency distribution. Accordingly, it becomes possible to separate signal elements from noise elements more accurately so as to further enhance the accuracy of magnetic character recognition.
(4) The method of magnetic character recognition: wherein the peak count evaluation process chooses a result of the peak searching process if the number of peaks in the waveform part agrees with a prescribed number of peaks, and the peak count evaluation process chooses a result of the character segmentation process if the number of peaks in the waveform part does not agree with the prescribed number of peaks.
According to at least an embodiment of the present invention; the peak count evaluation process chooses a result of the peak searching process or the character segmentation process, when the number of peaks in the waveform part agrees with a prescribed number of peaks or not, respectively. Therefore, it becomes possible to avoid any unnecessary chance of recognition impossible for the character in the course of operation of character recognition.
(5) An apparatus of magnetic character recognition through reading a character string by using a magnetic head, and creating a regeneration waveform for the character recognition; the character string including a plurality of magnetic characters printed with magnetic ink; and the apparatus of magnetic character recognition including: a peak detection section for detecting peak positions in the regeneration waveform; a character pitch measuring section for calculating an average character width and an average character period of each character according to a detection result of the peak detection section; a character segmenting section for calculating a peak interval array for each character according to the average character period; a peak searching section for searching for peak positions by using searching conditions, which are different from what the character segmenting section applies, on each waveform part segmented through the character segmenting section; a peak count evaluating section for choosing either a calculation result of the character segmenting section or a search result of the peak searching section, depending on whether the number of peaks in the waveform part agrees with a prescribed number of peaks; and a character determining section for a matching operation on a peak interval array, according to the peak interval array determined through the peak count evaluating section, to determine the character.
According to at least an embodiment of the present invention; the apparatus of magnetic character recognition includes: a peak detection section for detecting peak positions in the regeneration waveform; a character pitch measuring section for calculating an average character width and an average character period of each character; a character segmenting section for calculating a peak interval array for each character; a peak searching section for searching for peak positions by using searching conditions, which are different from what the character segmenting section applies; a peak count evaluating section for choosing either a calculation result of the character segmenting section or a search result of the peak searching section; and a character determining section for a matching operation on a peak interval array to determine the character. Therefore, an optimal peak interval array can be chosen through the peak count evaluating section and it is possible to recognize magnetic characters with high accuracy, even when the magnetic ink characters are printed, having their character pitch and character width that are unusual.